Biocatalytic processes such as those using numerous fermentable sugars as a substrate are seen as an economical and environmental alternative to traditional petrochemical processes. Biocatalytic processes involving conversion of low value carbohydrates, including agricultural and forestry waste, is of increasing interest due to the depletion of fossil derived hydrocarbon feedstocks used in petrochemical processes.
Succinic acid (SA) can be produced by microorganisms using fermentable sugars as a starting material. Most succinate producing microorganisms require neutralization of the fermentation broth to maintain an appropriate pH for maximum growth, conversion and productivity. Consequently, salts of SA such as monoammonium succinate (MAS) and diammonium succinate (DAS) are obtained by conversion of carbohydrates in the broth in the presence of succinate producing microorganisms. A cation elimination process is necessary to obtain the acid, wherein the base cation needed to neutralize the acid in the fermentation is replaced by protonation with a mineral acid such as sulfuric or electrodialysis. Conversion of the salt to the acid and its purification involve several unit operations that could potentially diminish the economic viability of biobased SA as a raw material for the production of runway deicers.
The runway deicer of interest is an aqueous mixed salt solution of dipotassium succinate/potassium acetate/potassium formate. Aqueous mixed salts of disodium succinate succinate/sodium acetate/sodium formate are also of interest. It is thus desirable to prepare the salt solution directly from the fermentation broth, without isolating and purifying the SA.
It could therefore be helpful to provide for economical production of a runway deicer from a fermentation mixture without first either separating and purifying SA or a succinate salt from the numerous impurities and particularly color bodies present in the fermentation broth.